1. Field of the Invention
This invention relates to printed circuit board (PCB) design. In particular, the invention relates to thermocouple junctions embedded in the printed circuit board.
2. Description of Related Art
Thermal dissipation increases as the frequency increases since thermal dissipation is a function of the square of the frequency. Given that bus frequencies have been increasing in tandem with the processor frequencies (e.g., speeds) and with the processor frequencies doubling every 18 months, thermal management poses significant technological challenges. In order to control the temperature of the critical components mounted on the PCB, it is necessary to monitor their temperatures accurately at or near the areas in which excessive heat is generated to prevent failure of these components. The current state of the art technique for measuring the temperature utilizes externally mounted thermocouple (TC) wire junction physically attached onto or brought in contact with the surfaces of the PCB or components of interest. The other ends of these wires are typically soldered to pads or vias in the PCB. Since it is difficult or impossible to insert the thermocouple junctions directly into the area underneath the mounted components, therefore, it is not possible to measure the temperature directly and accurately using this technique. It is also important to monitor and control the temperature of the PCB during a reflow process to ensure that the components are assembled under appropriate reflow conditions.
Therefore, there is need for better structure and technique to provide a better measurement of the temperature of the components on PCB and the PCB itself.